Breaking down bowel cancer

Leading experts recently agreed that bowel cancer should now be considered as four entirely distinct diseases. This is exciting news for science, but how does it help patients? We talk to Worldwide Cancer Research funded scientist and clinician Dr Louis Vermeulen, who was involved in this key piece of work published in Nature Medicinelast year.

You are part of the international consortium of experts, which recently established that bowel cancer is not one, but four different types of disease. How does each disease differ?

Basically everything is different! This classification really sheds new light on bowel cancer biology. The molecular and genetic characteristics of each different bowel cancer type are so diverse that we really do have to speak of four entirely separate diseases. The main thing they have in common is that all four are cancers which first emerge in the bowel, but apart from that they are very different indeed.

What does this new classification mean for patients? How do you think it will ultimately help them?

Until now we have been largely diagnosing and treating bowel cancer as one disease, but this classification really helps show that this is not the case.

Until now we have been largely diagnosing and treating bowel cancer as one disease, but this classification really helps show that this is not the case

I think we will now quickly be able to establish that some specific bowel cancer types do not respond very well to current drugs. So our first priority is to focus on improving treatments for these patients. We should also be able to identify the disease types that actually respond very well to treatments we already have. This knowledge alone will help us to better target our current treatments to situations where they are most likely to work.

We already see with some treatments like anti-EGFR agents (a targeted therapy used for the treatment of bowel cancer) that some groups of patients respond very well while others do not at all. I expect this finding could be implemented in clinical use very soon.

How does this new classification help bowel cancer research?

The new classification means each type of bowel cancer is now much more well-defined. This will help researchers more accurately explore the biology of each type and study how it develops and progresses. Because we now have a much better understanding of the various bowel cancer subtypes, we can already see new clues for novel drug targets.

With this new clearer picture of bowel cancer I hope it will become easier to generate new treatments. If an experimental treatment only works in some patients there is now a clear basis for why this is likely to be the case, and the researchers shouldn’t consider it a failure.

Ultimately I expect it will really help us and other scientists develop new therapies which can effectively treat all bowel cancer subtypes, even the types which are most aggressive and resistant to our current therapies. This will take time but the recognition of the various distinct diseases is a real breakthrough.

Ultimately I expect it will really help us and other scientists develop new therapies which can effectively treat all bowel cancer subtypes, even the types which are most aggressive and resistant to our current therapies

In addition, the success we have had in coming together and reaching this consensus shows that while scientists still compete to get to the breakthroughs first, when the need is high we can collaborate very effectively to get the important things done!

Do you expect these classifications to change? Could bowel cancer be divided into more and more subtypes as our knowledge about the disease increases?

In essence each patient’s bowel cancer is unique, so really each case deserves its own subtype. When developing this new classification we had to reach a trade-off between recognising this uniquely complex biology, while keeping it simple and practical enough for use in the clinic and clinical studies.

For now we have judged that classifying bowel cancer into four subtypes strikes this balance just right. But it’s certainly very possible that other rare types of bowel cancer, that have specific genetic alterations requiring specialised treatment for example, will be identified and included in future classification schemes.

Our classification is by no means perfect, but it’s the best we can currently provide. Now that we have it I am sure it will help to rapidly increase our understanding of the disease and optimise new and future therapies.

I'm grateful for the funding from Worldwide Cancer Research which really helped ensure we were able to take part and contribute meaningfully to this important decision.

I'm grateful for the funding from Worldwide Cancer Research which really helped ensure we were able to take part and contribute meaningfully to this important decision

Further information

Dr Louis Vermeulen is a lab leader at the Academisch Medisch Centrum in the Netherlands. You can read about his latest project with Worldwide Cancer Research here.

Read about how you could reduce your risk of bowel cancer in our earlier blog post.